Many devices with wheels and other motion propelled systems necessitate the use of locking mechanism to ensure safety of operation. The locking mechanism becomes even a more critical part of the system when nature of the activity promoted by the system can cause severe physical harm, or alternatively when user of the system is somehow impaired (minor, disabled etc.). Unfortunately, the locking mechanisms currently being used in the prior art do not always offer a safe or easy to use solution, For example, many of the commercial wheelchair designs have great shortcomings in this area. In order to understand the scope of this problem, it is useful to examine a typical wheelchair design in more detail.
It should first be noted that most wheelchairs and other such similar systems, often require the use of propulsion of a main driving wheel by the use of lateral actuation of a handle. The typical wheelchair has two large diameter wheels mounted toward the back, with two small diameter swivel wheels located in the front. The operator propels the wheelchair by grabbing a push rim mounted to the large diameter wheels and forcing the push rim forward, backward, or each side at different rates in order to turn. Wheelchairs work best on smooth, flat surfaces. However, the wheelchair operator cannot be limited to traversing ideal terrain in all situations. When the operator encounters a single obstacle, they can shift their weight appropriately to lighten the weight on the given wheel(s) and also exert a greater force on the push rims. The problem arises when the wheelchair operator traverses bumpy, uneven terrain typical of many off-road situations. On unpaved undulating terrain, each wheel may experience a dip or mound that the operator cannot easily overcome simply be transferring their weight. Currently, the operator of a typical wheelchair as exists in the prior art limited to amount of force they can generate and apply directly to the push rim.
Consequently, there is a need for an improved mechanism where the operator could apply a force to the wheels using a greater lever arm and could more easily traverse uneven terrain.